Our TASM active ruleset contains exceptions - I/O exceptions limited to 1 in the case - applying to queries when classification criteria are met (Teradata 15.00.04, Viewpoint 15.11.00)
In that context a query with SAMPLE bypassed the exception test and returned an answerset, although an error 3156 and Abort action is logged in dbqlogtbl and TdwmExceptionlog !
ErrorText column in dbqlogtbl is empty, ErrorText column in TdwmException is filled with "I/O:95159."
So Exception and Abort action are logged and the query returns rows: is that odd behaviour due to SAMPLE option ?
Other queries (same classification criteria) without sample are aborted as well ...
Was this a singular occurrence or something repeatable?
There is a small timing window between when TASM decides to trigger an exception and when the asynchronous abort request is actually processed.
it is repeatable.
I sent three queries (same user, profile and other classification criteria) from STUDIO:
1- select * from table sample 100; -- OK with errorcode 3156 (dbqlogtbl) and 100 rows in answerset
2- select * from table where UPI_column in ( 10 values); -- KO with errorcode 3156 (dbqlogtbl)
errortext (dbqlogtbl): "Request aborted by TDWM. Exception criteria exceeded: I/O Count."
3- select * from table sample 100; -- OK with errorcode 3156 (dbqlogtbl) and 100 rows in answerset.
PS: Exception is defined on I/O count limited to 1
Notice that a switch between SessionWDID and WDID is done according to criteria analysis.
Exception is associated to the workload in use when executing the query (WDID).